Method and apparatus for the production of mechanical power from hydraulic energy

ABSTRACT

The subject of the invention is an engine that is actuated by a fluid under pressure, preferably water, and comprises one or more oscillating, connecting-rod assemblies ( 13 ), including a cylinder ( 14 ) and a piston ( 15 ), and at least one or more cranks ( 16 ) driven by the connecting-rod assemblies ( 13 ). For each connecting-rod assembly ( 13 ), a preferably stationary valve ( 20 ) controls the feed and the discharge of the pressure fluid to and from it, synchronically with the angular position of the corresponding crank ( 10 ), and acts as the pivot about which connecting-rod assembly ( 13 ) oscillates. The engine can be applied for producing mechanical work in any apparatus, for example in sprinklers, concrete mixers, apparatus for winding cables or garden hose reels, and so on, or for the production of electrical energy. The actuating fluid can be used, after its discharge from the engine, for purposes for which high pressure is not required.

FIELD OF THE INVENTION

This invention relates to the production of mechanical power fromhydraulic energy; in particular, it relates to an engine that isactuated by a fluid, preferably water, or gas, preferably air, underpressure. It further relates to a mechanism for actuating a shaft bymeans of a pressure fluid which comprises an oscillating, connecting-rodassembly and at least a crank driven by said connecting-rod assembly, ashereinafter defined. The invention further relates to the use of such amechanism for actuating various mechanical apparatus. The inventionfurther relates to a valve for controlling the feed and the discharge ofpressure fluid to and from a connecting-rod assembly, synchronicallywith the angular position of the crank driven by said assembly.

BACKGROUND OF THE INVENTION

Fluid-actuated mechanisms for carrying out mechanical work are known inthe art and have been described in a number of patents. U.S. Pat. No.2,518,990 describes a fluid-actuated hose reel in a lawn sprinkler. U.S.Pat. No. 2,989,605 describes a water-powered retractable shower head.More recently, U.S. Pat. No. 5,741,188 discloses a ride-on toy or agarden tool which includes a stationary element, a movable elementconnected thereto, water pressure operating means for moving the movableelement with respect to the stationary element, a water inlet and awater outlet, and a valve for controlling the flow of the water throughthe device.

European Application 136414 A2 discloses a water flow operated devicefor winding and/or unwinding a layer of flexible material whichcomprises a stationary element, a spool having a central axis, saidspool being rotatable about a central axis when engaged with thestationary element; and a water flow-operated mechanism engaged by saidstationary element for controllably rotating said spool.

The provision of a generally or widely applicable motor operated by afluid under pressure (herein “a pressure fluid” or “an actuatingfluid”), in particular water, that is effective, simple in constructionand economical, is extremely desirable. It is therefore a purpose ofthis invention to provide such a motor.

It is another purpose of this invention to provide such a motor which isself-controlled, in the sense that it contains all the componentsnecessary for assuring its operation without the provision of separate,central control mechanisms.

It is a further purpose of this invention to provide such a motor whichcomprises a shaft, or a plurality of shafts, or a crankshaft, driveninto rotation by one or a plurality of oscillating-rod-crank couplings,which incorporates a control mechanism for actuating the oscillatingmotion of the rod in synchronism with the rotary: impulses required bythe rotating elements.

It is a still further purpose of this invention to provide afluid-actuated motor, in particular a water motor, for use in a varietyof apparatus requiring mechanical energy for various purposes.

It is a still further purpose of this invention to provide a mechanismwhich is actuated by a pressure fluid, in particular water, whichimparts rotational impulses to a crank or a crankshaft at a plurality ofangular positions of said crank or crankshaft.

It is a still further purpose of the invention to provide means forfeeding pressure fluid, in particular, water, to a cylinder, to actuatea piston and synchronize its alternating motion to the angular motion ofa rotating element, that is simple, self-contained and economical tobuild.

Other purposes and advantages of the invention will appear as thedescription proceeds.

SUMMARY OF THE INVENTION

In a first aspect thereof, the invention provides a mechanism foractuating a rotatable shaft from actuating or pressure fluid, whichcomprises a crank connected to the shaft for mutually dependent swingingmotion of the crank and rotation of the shaft; an angularly oscillatingconnecting-rod assembly comprising a cylinder and a piston, said pistonbeing pivotally connected to said crank for mutually dependentoscillation of said assembly and swinging motion of said crank; and avalve, preferably stationary valve, for permitting feed of actuatingfluid to said cylinder and permitting discharge of said fluid from saidcylinder, depending on the angular position of said connecting-rodassembly.

It is preferred that the stationary valve should acts as the pivot aboutwhich the connecting-rod assembly angularly oscillates. However, itwould be possible to provide a separate pivot and a separate stationaryvalve, as long as the valve permitted feed of actuating fluid to theconnecting-rod assembly cylinder and discharge of the fluid from saidcylinder, depending on the angular position of the connecting-rodassembly. This could be achieved, e.g., by placing a valve at anintermediate position of the connecting-rod assembly cylinder, viz.closer to the crank than the pivot; or by providing the connecting-rodassembly cylinder with an extension and placing the valve beyond thepivot, in such a position as to cooperate with that extension. Othersolutions could be devised by expert persons, by the application ofmechanical and kinematic know-how, and all such solutions areembodiments of the, invention. The invention therefore comprises anymechanical solutions whereby the operation of the valve is synchronizedwith the oscillating motion of the connecting-rod assembly.

Preferably, the stationary valve and the connecting-rod assembly arepivotally connected through respective pivot surfaces, said pivotsurfaces being provided with apertures for the passage of actuatingfluid. Said apertures become more or less juxtaposed depending on theangular position of said connecting-rod assembly, whereby said feed anddischarge of said fluid to and from the connecting-rod assembly areautomatically synchronized with the crank swinging motion.

The mechanism of the invention acts in combination with a source ofactuating fluid under pressure and with a discharge, communicating withthe stationary valve through fluid channels.

The actuating fluid is preferably water, but it may be another liquid,or may be gaseous—gas or vapor—particularly steam.

Traditional connecting-rod-crank mechanisms must be provided withcontrol means for admitting pressure fluid, in many cases compressed airor steam, to the, cylinder and dlischarging said pressure fluid from it.If more than one connecting-rod were provided, a plurality of controlmeans would have to be provided and synchronized, as required, to imparta rotational impulse to the crank at appropriate stages of its swingingmotion. In the mechanism of the invention, the admission and dischargeof the pressure fluid are controlled in each connecting-rod assembly bya valve, preferably a stationary valve which also operates as a pivot,and therefore are automatically synchronized with the stages of thecrank rotation.

In more detail, the preferred: form of the mechanism of the inventioncomprises a crank rotatably connected to a shaft either because it issolid with it, or is keyed to it, or is a part of a crankshaft. Theconnecting-rod assembly comprises a cylinder, which has a pivotalconnection to the crank, preferably wherein the cylinder is providedwith a pivot seat, such as an annular one, while the crank is providedwith a pivot pin or is part of a crankshaft which engages the pivotseat, the opposite being equally possible. The cylinder is provided witha pivot seat or surface, preferably being cylindrical or a segment of acylinder, which has an aperture providing a communication with theinside of the cylinder. The aperture may be a single, preferably anelongated, one, or may be constituted by a plurality of openings, e.g.,circular openings arranged one after the other along a line, in whichcases it will be called herein “composite aperture”. In a preferredembodiment of the invention the aperture, whether single or composite,is arranged on a transverse axial line or is symmetric with respect ofsaid line. “Transverse axial line” means herein the intersection of thepivot seat of the connecting-rod assembly cylinder with the plane ofsymmetry of the cylinder that passes through the axis of symmetry of thepivot pin of the crank and the pivot seat of the connecting-rod:assembly. It is preferred that said aperture of said pivot seat, whethersingle or composite, be symmetric to said transverse axial line, but itis possible that it be not so symmetric but arranged on a line that issymmetric with respect to said transverse axial line, as will be betterexplained later on.

The mechanism, in its preferred form, further comprises a stationaryvalve, the body of which is partly hollow, and which comprises an outerpivot surface slidingly engaged by the pivot seat of the connecting-rodassembly cylinder. Said pivot surface is a part of a cylinder orconsists of parts of a cylinder, while the remaining part of the outersurface of the valve body may have a different shape. The valve body hasa first and a second aperture communicating with its inner hollow, andwhich are preferably longitudinal, viz. symmetric with respect to anaxial plane of the valve body, but in general are so shaped that theymay be juxtaposed to said aperture of the pivot seat of theconnecting-rod assembly cylinder. Each of the valve body aperturescommunicates, through inner channels of the valve body, with arespective port. One of the two ports is in communication with a sourceof pressure fluid and the other one with or a fluid dischargerespectively, and thus communication is established between therespective apertures of the valve body and said pressure fluid source orfluid discharge, respectively. In some applications, as will beexplained hereinafter, the functions of the two ports are periodicallyswitched, viz. each communicates alternatively with said source ofpressure fluid and with said fluid discharge. In other applications, oneof the ports communicates always with said source of pressure fluid andthe other communicates always with said fluid discharge.

As the connecting-rod assembly oscillates, its angular position shiftsfrom one extreme end to another extreme end. The first and secondapertures of the valve body are angularly spaced by the same angle asthe two extreme positions of the connecting-rod assembly. At a givenangular position of said assembly, generally at the center or near thecenter of its oscillation, the aperture (whether single or composite,viz consisting of several openings close to one another) of said pivotseat or surface of the cylinder of the connecting-rod assembly isjuxtaposed to an unapertured portion of the valve body. As said assemblyoscillates, said aperture of said pivot seat or surface becomesgradually juxtaposed to one (first juxtapositions or to the other(second juxtaposition) of the apertures of the valve body. In the firstjuxtaposition, the inside of the cylinder is placed in graduallyincreasing communication with a source of pressure fluid which is fed tothe inside of the cylinder, and therefore the piston is subjected to anaxial force which it transmits to the crank or crankshaft as arotational impulse. In the second juxtaposition, the inside of thecylinder is placed in gradually increasing communication with thedischarge, there is gradually decreasing resistance to the motion of thepiston, and the fluid is gradually discharged from the cylinder. At oneof the extremes of the oscillation of the connecting-rod assembly, saidfirst juxtaposition is complete or at least at a maximum, and saidpiston is subjected to a maximum axial force; at the opposite extreme,and the discharge of the fluid from said cylinder is complete or atleast as complete as it will be. Said operative phases will be furtherdescribed hereinafter, with reference to FIG. 18.

For the sake of clarity, the outwardly or projecting motion of thepiston, with respect to the cylinder, from its innermost or mostretreated position to its outermost or most extended position, duringwhich it transmits to the crank a rotational impulse, will be called thepositive or active stroke, and the inwardly or retreating motion of thepiston from said outermost to said innermost position, during which itdischarges the fluid from the cylinder, will be called the negative orpassive stroke. As will be explained in detail hereafter, the choice ofwhich port communicates with a source of pressure fluid and whichcommunicates with a discharge depends on the phases of the swingingmotion of the crank, and is established so as to impart to the crank arotational impulse when this is desired and allow it to continue freelyin its swinging motion when-no further impulse is to be transmitted fromthe respective connecting-rod. It will be understood that, if the shaftconnected to the crank always rotates in the same direction, one portwill always be in communication with the source of pressure fluid andthe other port will always be in communication with the discharge.However, if the shaft is to rotate alternatively in opposite directions,the ports will periodically switch their aforesaid communications.

In one of the preferred embodiments of the invention, the crank isassociated with a plurality of connecting-rod assemblies, which areangularly spaced, preferably by the same angle. Each connecting-rodassembly has an angular position that can be called the “null” or “zeroangle position”, which is the position at which the axis of the pistonof the connecting-rod assembly and the radius of the crank are aligned.Actually, there are two such positions, in one of which the piston is atits greatest retraction, while in the other it is in its greatestextension. When it is said herein that various connecting-rod assembliesare angularly spaced from one another, what is meant is that the nullangle positions thereof are angularly spaced from one another.Preferably, the angular spacing is uniform, but this is not necessaryand dynamic considerations may suggest a different angular spacing.Since in a preferred embodiment of the invention three connecting-rodassemblies are provided, any two of them are adjacent to one another andare spaced from one another by 120° or by any other chosen angle. Theconnecting-rod assemblies, however, when a plurality of them is present,need not be at an angle to one another but may be linearly spaced, viz.placed one next to the other in such a way that the axes of their nullangle positions are all coplanar, parallel to one another in the commonplane, and displaced from one another perpendicularly to their commondirection. In this case, each connecting-rod assembly operates on adifferent crank and all the cranks are part of a crankshaft. Anapparatus in which the connecting-rod assemblies are linearly spaced isalso a preferred embodiment.

Another aspect of the invention is the provision of an apparatus for theproduction of mechanical work from hydraulic energy, which comprises asource of pressure fluid and a mechanism for actuating at least onerotatable shaft from the said pressure fluid, as hereinbefore described.

Preferably, the invention also comprises the use of the mechanismhereinbefore described for producing mechanical work the mechanism canbe applied for producing mechanical work in any apparatus. Among suchapplications are, for example, sprinklers, mixers, in particularconcrete mixers, apparatus for winding cables or garden hose reels, forspreading pool covers, for actuating shading canvases, valve controlmotors, robots for cleaning swimming pools, ride-on garden toys, coolingfans, rotary watering filters, and the like. The mechanism can also beused for the production of electrical energy, viz. can be coaxial withor otherwise drive an electricity generator it should be noted that, insome cases of engines according to the invention, the actuating fluidcan be used, after its discharge from the engine, for other purposes forwhich only a low pressure or no pressure at all is required. Forinstance, if the fluid is water, the discharged water may be used inwater sprinklers, drip systems, humidification of cooling fans,supplying water to cement mixers, and the like. Such a further use andthe resulting apparatus are also aspects of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIGS. 1A, 1B and 1C illustrate the motion of the connecting-rod assemblyduring the phase of the rotation of the crank in which a rotationalimpulse is to be transmitted to said crank, according to an embodimentof the invention;

FIGS. 2A, 2B and 2C illustrate the motion of the connecting-rod assemblyduring the phase of the rotation of the crank in which no impulse is tobe transmitted to said crank, according to the embodiment of FIG. 1;

FIG. 3 is a schematic cross-section of the connecting-rod assembly andthe valve, axial with respect to the assembly and transverse withrespect to the valve, according to an embodiment of the invention;

FIG. 4 illustrates in exploded perspective the relationship between theconnecting-rod assembly and the valve, according to an embodiment of theinvention;

FIG. 5 illustrates in perspective view the valve of FIG. 4, whichrelates to a motor that rotates in one direction;

FIGS. 6 and 7 illustrate an embodiment of the invention in which theconnecting-rod assemblies and the valves are spaced linearly;

FIGS. 8 and 9 illustrate an embodiment of the invention which comprisesthree angularly spaced connecting-rod assemblies;

FIG. 10 illustrates in perspective view the use of the apparatus ofFIGS. 8 and 9 in a mixer;

FIGS. 11 and 12 are schematic cross-sections of pistons of theconnecting-rod assembly, according to two embodiments of the invention;

FIG. 13 illustrates in perspective view a variant of the valve of FIG.5, which relates to a motor that rotates in two directions;

FIG. 14 is a schematic cross-section analogous to FIG. 3, but embodyingthe valve of FIG. 13;

FIG. 15 is an enlarged cross-section of the valve of FIG. 14;

FIG. 16 illustrates in schematic perspective view a use of theembodiment of FIGS. 6 and 7 in a hose reel;

FIG. 17 illustrates in schematic perspective view a use of theembodiment of FIGS. 8 and 9 in a fan;

FIG. 18 is an enlarged cross-section of the valve body, illustrating thephases of its operation; and

FIG. 19 is a cross-sectional detail of the valve body, illustrating adevice for preventing leakage of fluid under pressure.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The operation of a connecting-rod assembly according to an embodiment ofthe invention will be understood with reference to FIGS. 1A, B, C andFIG. 2A, B, C. FIG. 1 illustrate the motion of the connecting-rodassembly during the phase of the rotation of the crank in which arotational impulse is to be transmitted to said crank. During saidphase, the piston of said assembly moves in its positive or activestroke. FIG. 2 illustrate the motion of the connecting-rod assemblyduring the phase of the rotation of the crank in which no impulse is tobe transmitted to said crank. During said phase, the piston of saidassembly moves in its negative or inactive stroke.

As seen in FIG. 1; numeral 10 indicates a shaft, which rotates, togetherwith a crank 16, solid with it or keyed to it, about an axis 11 in thedirection indicated by the arrow 12. 13 generally indicates theconnecting-rod assembly. 14 is the cylinder of said assembly and 15 isthe piston. Piston 15 is connected to crank 16 by a pivotal connectiongenerally indicated at 17.

The connecting-rod assembly 13 is pivoted to a stationary valve 20, onlyone end of which is visible in FIG. 1, showing port 21 whichcommunicates either with the source of pressure fluid or with thedischarge. Another port communicates with the discharge or with a sourceof pressure fluid, respectively, and can be provided on the opposite end(not visible in the drawing) of the valve.

In FIG. 1A the connecting-rod assembly 13 is in its first null angleposition, which will be called herein the “retracted” null angleposition, or briefly, “the retracted position”. Line 22, which is thetrace on the drawing of the plane of symmetry of cylinder 14 and piston15, passes through the axis of the shaft 10. The valve axis, the crankaxis and the shaft axis are on one plane. Piston 15 is retracted insidecylinder 14 as far as it will go. As crank 16 rotates as shown by arrow12, connecting-rod assembly 13 rotates in an opposite direction, asshown by arrow 24, about valve 20, which acts as a stationary pivot.

In the position of FIG. 1B, the connecting-rod assembly has rotated byan angle α, which is the maximum one. Piston 15 has accomplished part ofits active stroke.

As the motion of the mechanism continues, as shown in FIG. 1C, itreaches its second null angle position, which will be called herein the“extended” null angle position, or briefly, “the extended position”. Thecenter of valve 20, the axis of cylinder 14, the axes of piston 15, ofshaft 10 and of pivot connection 17 are all on the same plane, the traceof which on the drawing is indicated at 25. The active or active strokeof piston 15 has come to an end.

FIG. 2 shows the second phase of the operation of the connecting-rodassembly. At the starting point, in FIG. 2A, it is in its extended nullangle position, as in FIG. 1C. In FIG. 2B, it is in a position symmetricto that of FIG. 1B. The piston 15 has reentered partly into cylinder 14,and they both have reached the outermost angular deviation of theconnecting-rod assembly from its null angle positions, indicated by anangled symmetric to that of FIG. 1B.

As the motion of the mechanism continues, piston 15 accomplishes itsnegative or passive stroke and retracts into cylinder 14 as far as itcan go. At FIG. 2C, the apparatus has reached the same position as inFIG. 1A, viz. its retracted null angle position.

It is apparent therefore that pressure fluid, particularly water, mustbe introduced into cylinder 14 while it swings from the position of FIG.1A to that of FIG. 1C, and must be discharged while it swings from theposition of FIG. 2A (the same as that of FIG. 1C) to that of FIG. 2C(the same as that of FIG. 1A).

FIG. 3 generally illustrates, in a cross-section that is axial withrespect to connecting-rod assembly 13 and the valve 20. The assembly 13comprises a cylinder 14 and a piston 15, provided with a sealing ring11. (see also FIG. 11). Numeral 30 indicates a cylindrical surface,spanning an arc of about 240°, which serves as a pivot seat for a pivotpin driven by the crank 16. This embodiment is desirable when the pistonis made of plastic matter, because then the pivotal connection betweenthe piston 15 and the crank 16 may be obtained by snapping surface 30over the pivot pin driven by the crank 16. In other embodiments, such asthat of FIG. 4, the pivot seat is a fill ring and must be slid over thepivot pin. The cylinder 14 of the connecting-rod assembly terminateswith a transverse cylindrical portion 31. By “transverse cylindricalportion” is mean therein a portion of a cylinder the axis of which isparallel to the axis about which the connecting-rod assembly oscillates.Within said cylindrical portion 31 is inserted a valve body 32 and saidportion 31 is open, at least at one end, to permit the introduction ofsaid valve body. Said cylindrical portion 31 has an aperture 36, throughwhich fluid may be fed into the cylinder 14 or discharged therefrom.Said aperture may be single and preferably symmetric about a centraltransverse line which is the intersection of said cylindrical portionwith a plane of symmetry of the connecting-rod assembly passing throughthe axis about which the connecting-rod assembly oscillates and the axisof the crank pin. Said aperture may be composite, viz. consisting of aplurality of openings close to one another and centered on said centraltransverse line. Optionally, however, though less preferably, it couldbe arranged about a line slanted with respect to said central transverseline, or about a curved line, said slanted or curved line beingsymmetric with respect to said central transverse line.

In FIG. 3, the cylinder 14 of the connecting-rod assembly, is shown in aposition in which aperture 36 of cylindrical sleeve 31 overlapspartially aperture 38 of the valve body and partially a rib 35 of thevalve body 32. In either of the null angle positions (only one of thembeing marked in the drawing) the aperture 36 would be placed on a line37 which coincides with line 22 of FIG. 1A, and would be stoppered(closed) by said rib 35. As the connecting rod assembly swings one wayor the other from a null angle position, the aperture 36 comes intogradually increasing juxtaposition to one or the other of two apertures38 and 39 of the valve body. The phases of said juxtaposition areillustrated in the enlarged cross-section of the valve body 32 in FIG.18, wherein the cylindrical portion 31 is in its central position andthe aperture 36 is closed by rib 35 of valve body 32 (see FIG. 3). Assaid cylindrical portion 32 swings clockwise (as seen in FIG. 18) in theoscillation of the connecting-rod assembly, aperture 36 graduallyoverlaps aperture 38 of the valve body, until, after clockwise rotationby an angle α, point A coincides with point C, or is as close aspossible to it, and the overlapping of aperture 36 with aperture 38reaches a maximum. If said cylindrical portion 32 swingscounterclockwise. (as seen in FIG. 18), said overlapping decreases untilit is annulled in the central position shown in the figure, and as thecounterclockwise rotation continues, aperture 36 gradually overlapsaperture 39 of the valve body, until, after counterclockwise rotation byan angle α, point D coincides with point F, or is as close as possibleto it, and the overlapping of aperture 36 with aperture 39 reaches amaximum.

Apertures 38 and 39 are in communication with inner channels 33 and 34which lead to opening 21, or to an equivalent opening, not shown in thedrawing, and located on the opposite side of the valve. One of theseports is in communication with a source of pressure fluid, while theother port is in communication with the discharge; but, as has been saidhereinbefore, in some embodiments said communications may beperiodically switched. Switching of communications causes the inversionof the motor direction of rotation. Aperture 36 of the connecting-rodcylinder becomes gradually juxtaposed to one of openings 38 and 39, ashas been explained, during the swinging of the connecting-rod assemblybetween the two maximum angular deviations shown in FIG. 1B and FIG. 2B,and becomes juxtaposed completely or to the maximum degree at either ofthe said two extreme angular positions which the cylinder 14 may assume.It is seen therefore that when the mechanism swings towards the positionof FIG. 1B, pressure fluid will be gradually admitted through one of theapertures 38 or 39, while, when the mechanism swings towards theposition of FIG. 2B, pressure fluid will be gradually discharged throughthe other of said apertures.

FIG. 4 is a further illustration in exploded perspective of therelationship between the connecting-rod assembly and the valve. Piston15 is seen as outside of cylinder 14. In this and in other figures, thepiston is seen as not as solid as in FIG. 3, but as formed by a numberof longitudinal ribs 40, which is desirable for the purpose oflightening the apparatus, particularly in plastic pieces in which thinflat portions are preferred. 42 is the pivot seat, shown herein asring-shaped. Elastomeric seals, such as seal ring 44, are provided toassure that the fluid should not pass around or through the piston fromthe bottom of cylinder 14 through which it is admitted or discharged.FIGS. 11 and 12 schematically show in cross-section two ways forproducing a seal in plastic pistons. The piston body is shown as full inthese figures, but this representation is only schematic and the pistonwill have any desired cross-section. In FIG. 11, the piston generallyindicated at 100, is provided with an annular rubber seal 101. In FIG.12, the piston 102 has a flexible edge 103, which serves as a seal, andis an integral part of the piston. The valve body, generally indicatedin FIG. 4 at 45, is illustrated as being outside the cylindrical seat31, in which it is received during the operation of the device. Thevalve body 45 is better illustrated in FIG. 5. It is shown herein aspartly cylindrical in order to provide smooth motion of the sleeve 31about the body 45 of the valve. 109 and 109′ are two seal rings. If thevalve body is precise in its shape and dimensions, as it may be if it ismade of metal it will closely fit sleeve 31 and there will be no fluidleakages. However, if it is not precise in its shape, particularly whenmade of plastic, additional means must be provided to prevent leakage atleast about the aperture 38 (or 39) through which passes actuating fluidunder pressure, although leakage may not be a serious danger when thefluid flows to the discharge. A means for this purpose is illustrated inFIGS. 5 and 19. FIG. 19 is an enlarged cross-section of a singleaperture 38 of the valve body, the rest of said valve body beingomitted. The cylindrical portion 31 of the connecting-rod assemblycylinder and the valve body 45 do not match precisely and a gap 40exists between them. The aperture 38′ through which passes actuatingfluid under pressure, indicated at 104, has an edge 105 spaced from theedge 106 of a broader opening of the valve body (see FIG. 5). Anelastomeric sleeve 107: fits tightly over edge 105. A rigid cap 108,e.g. of plastic, having a very thin radial wall 108′, fits tightly overelastomeric sleeve 107, but can slide over edge 106. It is provided withan aperture, indicated at 38′ because it has the function of thepreviously described aperture 38 (or 39). The elastomeric sleeve 107pushes the rigid cap 108 outwardly until the radial wall 108′ of the capis flush with the valve body surface. Sleeve 107, therefore, functionsas a spring forcing cap 108 outwardly and as a seal between the cap andthe valve body, while the radial wall 108′ of the cap functions as adiaphragm urged by the fluid pressure against the inner surface of thecylindrical part 31, whereby to improve sealing.

If the shaft driven by the mechanism always rotates the same direction,fluid and only one seal is required. If the shaft driven by themechanism alternatively rotates in opposite directions, both valve bodyports alternatively communicate with the source of pressure fluid andboth must be provided with a seal-cap unit as hereinbefore described.This is illustrated in the exploded perspective of FIG. 13, in thecross-section of FIG. 14, and in the enlarged partial cross-section ofFIG. 15. In FIG. 13, the valve body 45 is provided with two ports 21 and21′ for communication with a fluid source and with a dischargerespectively. Two elastomeric seal rings 109 and 109′ are mounted onsaid body. Two openings 110 and 110′ of the valve body accommodate twoapertures 38 and 39. For aperture 38, are provided elastomeric sleeve107 and rigid cap 108, having the functions described in connection withFIG. 5. Similar elastomeric sleeve 111 and rigid cap 112 are provided tocarry out the same functions for aperture 39. Opening 110 of the valvebody can be broad enough to accommodate two apertures 38 and 39. In suchconfiguration, elastomeric sleeves 107 and 111, and rigid caps 108′ and112, could be connected to form a single elastomeric sleeve and/or asingle rigid cap. FIG. 14 is an axial cross-section of the connectingrod assembly and a transverse cross-section of the valve. Theconnecting-rod assembly 13 is the same as in, FIG. 11 but the piston 100is provided with an elastomeric seal 101, as in FIG. 11. The valve body,45 is better seen in FIG. 15, which is an enlarged cross-sectionthereof, taken across apertures 38 and 39. 113 and 114 are two channelsthrough which said apertures communicate with port 21 and, acorresponding port on the other side of the valve body. The twoelastomeric sleeves are seen at 107 and 111 and the two rigid caps at108 and 112.

FIGS. 6 and 7 illustrate an embodiment of the invention in which thecranks are part of a crankshaft and the connecting-rod assemblies andthe valves are spaced linearly, perpendicularly to their axes in thenull angle positions. In FIG. 6, numeral 50 indicates a crankshaft whichcomprises three cranks 51, 52 and 52′. Corresponding to each of saidcranks, the apparatus comprises three connecting-rod assemblies, whichcomprise pistons 53, 54 and 55, and cylinders 56, 57 and 58. Saidassemblies are similar to those of the embodiment previously described.Valve 60, 61 and 62, similar to those hereinbefore described, serve aspivots of the connecting-rod assemblies, being inserted respectivelyinto sleeves 63, 64 and 65. Valves 60, 61 and 62 can be designed as oneunit. Numeral 66 indicates a cover element overlapping the apparatus and67 is a plate attached to one end of over 66, provided with a projectionthat serves as a support to engage a stationary frame. 68 is a shapedprojection for engaging the crankshaft 50 to any chosen drivenapparatus.

FIG. 7 shows in perspective view the assembly of the crankshaft, theconnecting-rod assemblies with their terminal sleeves and the valves,not visible because enclosed in the terminal sleeves. This figure alsoshows at 70, 71 and 72 the pivotal connections between the pistons andthe crankshaft. In FIG. 7, the device is shown in different angularpositions of the three connecting-rod assemblies. Piston 53 isapproximately at the end of its positive stroke and piston 72 is at ornear the end of its negative stroke.

FIGS. 8 and 9 illustrate in perspective view an embodiment of the devicewhich comprises the three connecting-rod assemblies 80, 81 and 82. Theycomprise three cylinders 83, 84 and 85 respectively and pistons 86, 87and 88 respectively. The crank which they drive is identified by numeral89 and is solid with or keyed to shaft 92. 91 indicates a supportingplate. In FIG. 9 the device is shown in exploded perspective view, inwhich the crankshaft 90 is clearly visible. The three cylinders 83, 84and 85 of the connecting-rod assemblies are provided with transversesleeves 93, 94 and 95, respectively for housing valves 96, 97 and 98respectively. The valves are supported on a trilateral support 99attached to a support plate 91.

FIG. 10 illustrates in perspective view an embodiment in which theapparatus of FIGS. 8 and 9 is used to drive a cement mixer 100. Thecement mixer is supported on a base 101 by means of legs 102, to whichthe axis of the cement mixer is pivoted. The device according to theinvention, such as illustrated in FIGS. 8 and 9, is generally indicatedat 103 and is supported on a transverse bar 104. The threeconnecting-rod assemblies are visible and indicated by the said numerals80, 81 and 82, as in FIG. 9. A handle 105 permits to rotate the mixermanually, as may be required to place it in an angular position, forloading or unloading.

FIG. 16 shows in perspective view a mechanism such as that of FIGS. 6and 7, mounted on a garden hose reel with a stationary stand 120. Themechanism is provided with a cover. 121, partly broken off to show partof the connecting-rod assemblies. 122 generally indicates the drivenreel of the hose reel. In this configuration, the mechanism/motoraccording to the invention is located inside the reel.

FIG. 17 illustrates in exploded perspective view the use of a mechanismsuch as that of FIGS. 8 and 9 for driving a fan schematically indicatedat 126. Mechanism 125 is supported on a stand 127.

While specific embodiments have been shown by way of illustration, itshould be understood that the invention can be carried out with manymodifications, variation and adaptations, without departing from itsspirit or exceeding the scope of the claims.

1-25. (canceled)
 26. A fluid-driven engine, comprising: a drive unit(13) connectable to a source of pressurized fluid and including a piston(15) movable within a cylinder (14); a valve assembly (20) controllingthe introduction of pressurized fluid into said cylinder (14), and thedischarge of spent fluid therefrom for driving said piston (15) withrespect to said cylinder; and a rotatable drive shaft (10) including acrank arm (16) coupled to said drive unit (13) for rotating said driveshaft about a rotary axis (11); said piston (15) projecting through oneend of said cylinder (14) and being pivotally coupled to said crank arm(16) for rotating said drive shaft (10) during forward and returnstrokes of the piston with respect to the cylinder; the opposite end ofsaid cylinder (14) being pivotally mounted to said valve assembly (20)so as to oscillate with said piston (15) between opposite sides of saiddrive shaft rotary axis (11) during the forward and return strokes ofthe piston; said opposite end of the cylinder (14) being formed with aport (36) through which pressurized fluid is introduced and spent fluidis discharged as controlled by said valve assembly (20) during theoscillations of said cylinder and piston (15); characterized in thatsaid valve assembly (20) includes a valve body (32, 45) of cylindricalconfiguration pivotally mounting said opposite end of the cylinder (14)for pivotal movement about the longitudinal axis of the valve body; saidvalve body including a cylindrical surface serving as the pivotalmounting seat for said opposite end of the cylinder and formed with apair of valve openings (38, 39) circumferentially spaced from each otherso as to be selectively alignable with said port (36) formed in saidopposite end of the cylinder during pivotal movements of said cylinderfor controlling the introduction of pressurized fluid into the cylinderand the discharge of spent fluid from the cylinder.
 27. The engineaccording to claim 26, wherein said valve openings (38, 39) are ofrelatively long length in the axial direction of said cylindricalsurface of the valve body (FIGS. 4, 5, 13) and of relatively narrowwidth in the circumferential direction of said cylindrical surface ofthe valve body.
 28. The engine according to claim 26, wherein said valveopenings (38, 39) are of generally rectangular configuration.
 29. Theengine according to claim 26, wherein said opposite end of the cylinder(14) is formed with a cylindrical socket (31) receiving said valve body(45, FIG. 4) for pivotal movement of the cylinder and piston (15) withrespect to the longitudinal axis of the valve body.
 30. The engineaccording to claim 29, wherein said cylindrical surface of the valvebody further includes a pair of sealing rings (109, 109′, FIG. 5) on theopposite sides of said valve openings (38′, FIG. 5).
 31. The engineaccording to claim 26, wherein said valve body (45) includes a cap (108)for at least one of said valve openings, and an elastomeric sleeve (107)between the valve body and the cap for urging the cap against thesurface of said cylinder when pivotally mounted to the valve body. 32.The engine according to claim 26, wherein said valve body (45) includesa cap (108, 112, FIG. 13) for each of said valve openings (38, 39), andan elastomeric sleeve (107, 111) between the valve body and therespective cap for urging the respective cap against the surface of thecylinder (14) when pivotally mounted to the valve body.
 33. The engineaccording to claim 26, wherein said valve openings 38, 39 are ofrelatively long length in the axial direction of said cylindricalsurface of the valve body (FIG. 13) and of relatively narrow width inthe circumferential direction of said cylindrical surface of the valvebody; and wherein said valve body 45 includes a cap (108, 117) for atleast one of said valve openings, and an elastomeric sleeve (107, 111)between the valve body and the cap for urging the cap against thesurface of said cylinder pivotally mounting the cylinder and piston tothe valve body.
 34. The engine according to claim 33, wherein said valvebody includes a said cap (108, 112) and a said elastomeric sleeve (107,111) for each of said valve openings (38, 39).
 35. The engine accordingto claim 26, wherein said crank arm (16) of said drive shaft (10)includes a coupling pin (17), and wherein said one end of the piston(15) is formed with a snap ring (30) configured to be snapped onto saidcoupling pin.
 36. The engine according to claim 26, wherein said crankarm (16) of said drive shaft (10) includes a coupling pin (17), andwherein said one end of the piston (15) is formed with a coupling ring(42) dimensioned to be rotatably received on said coupling pin.
 37. Theengine according to claim 26, wherein said engine comprises a pluralityof at least three of said drive units (FIGS. 6-10, 16, 17) eachincluding a piston (53, 54, 55) movable within a cylinder (56, 57, 58);and a valve assembly (60, 61, 62) for each of said drive units forcontrolling the introduction of pressurized fluid into the cylinder ofthe respective drive unit and the discharge of spent fluid therefrom fordriving the piston of the respective drive unit; each of said pistons(53, 54, 55) being coupled to said drive shaft such that the pistonsinitiate their respective forward strokes at different angular positionsof the drive shaft.
 38. The engine according to claim 37, wherein saidpistons (53, 54, 55) are coupled to said drive shaft such as to initiatetheir respective forward strokes at equally-spaced angular positions ofthe drive shaft.
 39. The engine according to claim 37, wherein saiddrive units and valve assemblies are each arranged in a linear array(FIGS. 6, 7), with the valve assembly (63, 64, 65) at one end of therespective drive unit and in abutting relation to the valve assembly ofthe adjacent drive unit, and with the drive shaft coupled to the pistons(53, 54, 55) at the opposite ends of the drive units.
 40. The engineaccording to claim 39, wherein the pistons (53, 54, 55) of the driveunits are coupled to said drive shaft via a crank shaft (50) whichincludes a crank arm (51, 52, 52′) for each piston.
 41. The engineaccording to claim 37, wherein said drive units and valve assemblies arearranged in a radiating array (FIGS. 8-10, 16, 17), with the valveassembly (94, 95, 96) at the outer end of the respective drive unit andpivotally coupled to the cylinder (83, 84, 85) of the respective driveunit, and with the drive shaft at the inner ends of all said drive unitsand coupled to the pistons (86, 87, 88) of all the drive units.
 42. Theengine according to claim 41, wherein said drive shaft includes a singlecrank arm (89) to which the pistons of all the drive units are pivotallycoupled.
 43. A fluid-driven engine, comprising: a plurality of driveunits (FIGS. 6-10, 16, 17) connectable to a source of pressurized fluid;each of said drive units including: a piston (53, 54, 55) movable withina cylinder (56, 57, 58); a valve assembly (60, 61, 62) controlling theintroduction of pressurized fluid into the cylinder of each drive unit,and the discharge of spent fluid therefrom for driving the piston of therespective drive unit; and a rotatable drive shaft (10) coupled to saiddrive units for rotating the drive shaft about a rotary axis (11); eachof said pistons (53, 54, 55) projecting through one end of itsrespective cylinder (56, 57, 58) and being coupled to said drive shaftfor rotating said drive shaft during forward and return strokes of thepistons with respect to their cylinders; the opposite ends of thecylinders (56, 57, 58) being pivotally mounted to their respective valveassemblies (60, 61, 62) so as to oscillate with their respective pistonsbetween opposite sides of the drive shaft rotary axis (11) during theforward and return strokes of the pistons; the opposite end of each ofthe cylinders (56, 57, 58) being formed with a port (36) through whichpressurized fluid is introduced and spent fluid is discharged ascontrolled by the respective valve assembly during the oscillations ofthe cylinders and pistons; characterized in that there are at leastthree of said drive units, and in that the pistons of said drive unitsare coupled to the drive shaft such as to initiate their respectiveforward strokes at different angular positions of the drive shaft. 44.The engine according to claim 43, wherein each of said valve assemblies(60, 61, 62) includes a valve body (32, 45) of cylindrical configurationpivotally mounting said opposite end of the cylinder (14) for pivotalmovement about the longitudinal axis of the valve body; said valve bodyincluding a cylindrical surface serving as the pivotal mounting seat forsaid opposite end of the cylinder and formed with a pair of valveopenings (38, 39) circumferentially spaced from each other so as to beselectively alignable with said port (36) formed in said opposite end ofthe cylinder during pivotal movements of said cylinder for controllingthe introduction of pressurized fluid into the cylinder and thedischarge of spent fluid from the cylinder.
 45. The engine according toclaim 44, wherein each of said valve openings (38, 39) is of relativelylong length in the axial direction of said cylindrical surface of thevalve body (FIGS. 4, 5, 13) and of relatively narrow width in thecircumferential direction of said cylindrical surface of the valve body.46. The engine according to claim 43, wherein said pistons (53, 54, 55)are coupled to said drive shaft such as to initiate their respectiveforward strokes at equally-spaced angular positions of the drive shaft.47. The engine according to claim 43, wherein said drive units and valveassemblies are each arranged in a linear array (FIGS. 6, 7), with thevalve assembly (63, 64, 65) at one end of the respective drive unit andin abutting relation to the valve assembly of the adjacent drive unit,and with the drive shaft coupled to the pistons (53, 54, 55) at theopposite ends of the drive units.
 48. The engine according to claim 45,wherein the pistons (53, 54, 55) of the drive units are coupled to saiddrive shaft (50) via a crank shaft which includes a crank arm (51, 52,52′) for each piston.
 49. The engine according to claim 43, wherein saiddrive units and valve assemblies are arranged in a radiating array(FIGS. 8-10, 16, 17), with the valve assembly (94, 95, 96) at the outerend of the respective drive unit and pivotally coupled to the cylinder(83, 84, 85) of the respective drive unit, and with the drive shaft atthe inner ends of all said drive units and coupled to the pistons (86,87, 88) of all the drive units.
 50. The engine according to claim 47,wherein said drive shaft includes a single crank arm (89) to which thepistons of all the drive units are pivotally coupled.